The launchers for radio controlled flights of model airplanes have previously been provided to hold a model airplane in place before takeoff, during a time when a pilot is checking out the engine performance, and, as necessary, other performance functions as well.
In 1979, Oba L. St. Clair in his U.S. Pat. No. 4,169,333 illustrated and described his Model Aircraft Launcher for releasing a self-propelled model aircraft at a remote location, upon pulling on a control cord of the launcher. When this control cord was pulled, a release member of the launcher was slidably moved over a portion of a spring arm, finally disengaging this spring arm into a released position, thereby clearing and releasing a short retarding line holding a rear portion of the fuselage of the model aircraft, which was then ready for takeoff.
In 1991, Fred G. Hosage in his U.S. Pat. No. 4,993,672, illustrated and described his Safety Retainer For Model Airplanes. A U-shaped member was inserted into the ground. Then, via hinges, a hinged member was secured to it and arranged for rotation only in one direction opposite to the starting flight direction of the model airplane. Portions of the hinged member, when raised, retained the stabilizers of the model airplane. When the model airplane was ready for flight, a person pulled the model airplane back so the portions of the hinged member would rotate down clear of the stabilizers. Then when the person released the model airplane it was cleared for takeoff.
Mr. St. Clair provided his launcher to avoid the necessity of having an assisting person hold the model airplane while remaining in the exhaust stream of the engine. This person or the pilot standing at a remote location, upon pulling on the releasing-control cord, could clear the model airplane for takeoff. Mr Hosage did not provide this advantage for the assisting person or the pilot. Either one would have to be positioned to the rear of the model airplane to withdraw it, thereby allowing the raised portions of the hinged member to rotate down to ground level, clearing the model airplane for takeoff. However, Mr. Hosage did provide pivotal raised portions, which conveniently contacted the stabilizers of the model airplane when flight preparations were underway.
There remained a need for an improved launcher of model airplanes which did not require any person to subject himself or herself to the engine exhaust stream during flight preparations, and which would meet all of the necessary safety considerations.